The present invention relates to a tongue for a seatbelt buckle.
Seatbelt systems for vehicles usually comprise a length of seatbelt webbing wound on a rotatable spool that is part of a retractor controlling payout of the webbing. One end of the webbing is fixed to the retractor, which is mounted to a load bearing part of the vehicle such as a side pillar. The webbing extends from the retractor vertically up the side pillar to a webbing loop known as a D-ring at the vehicle occupant""s shoulder. The webbing then passes diagonally across the vehicle occupant""s torso to a buckling mechanism attached to the floor of the vehicle between the seats. The webbing then passes back across the vehicle occupant""s lap where the other end of the webbing is fixed to the floor of the vehicle adjacent the other side of the seat.
The buckling mechanism comprises a metal tongue releasably engaging a buckle. The webbing is looped through an aperture or slot in the tongue. When the seatbelt is unfastened, the webbing is re-wound onto the retractor and the tongue is pulled away form the buckle. In this stored position the tongue slides on the webbing and can fall to the floor of the vehicle, which is inconvenient for the occupant. To prevent this, webbing stops have previously been incorporated into the webbing in the form of rubber or plastic attachments molded or otherwise applied to the webbing, to resist the tongue sliding more than a predetermined distance down the webbing in the stored position. However such attachments in the webbing can interfere with the correct fitting of child seats in the vehicle and prevent the free run of webbing through the tongue slot when no vehicle occupant is present. This means that the three point system will not necessarily pass the latest safety regulations which require that a minimum tension be attainable in the lap portion of the belt by external application of tension in the diagonal section, even when no vehicle occupant is restrained in the seat.
The present invention provides an improved webbing stop that does not interfere with the characteristics of the seatbelt system such as to reduce the tension achievable in the lap portion or prevent the system being safely used with child seats.
According to the present invention, there is provided a seatbelt buckle tongue for a vehicle safety restraint system. The tongue comprises a buckling part and an aperture through which seatbelt webbing passes, wherein the extent of sliding of the tongue on the webbing is limited by one or more protrusions provided on the inside of the aperture in the tongue.
Preferably the protrusion is dimensioned and arranged to apply pressure to the webbing passing through the tongue to resist a sliding movement of the tongue on the webbing.
According to a preferred embodiment of the invention, the aperture in the tongue through which the webbing passes has two convex edges and the protrusion is positioned on one of the convex edges of the aperture. The protrusion is positioned such that it only protrudes into the webbing path when the tongue is in the stored, vertical, position. Furthermore, the protrusion is positioned such that the weight of the tongue causes sufficient friction between the webbing and the button to hold the tongue in position on the webbing and prevent it sliding downwardly.